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With the actual mean free path for radiation in air and a simplified nuclear device, a one-dimension simulation research on fireball phenomenon in a sea level atmosphere is carried out based on the multi-group radiation hydrodynamic codes (RDMG). It is shown that our theoretical calculations can describe the whole process of the fireball evolution for strong explosions from the early X-ray expansion stage to the shock wave propagation stage. The radius of the shock wave and the brightness of the fireball are in good agreement with the experimental results. The whole thermal radiation power curve of the fireball evolution for strong atmospheric explosion at sea level is plotted for the first time. The impact of radiation opacity of the nuclear device material on the early fireball phenomenon is also studied. It is found that trajectories of the radiation fronts and case shocks change with the opacity of equivalent device material. From our simulations, we find that only the early fireball depends on the details of the nuclear device, and after the formation of main shock, the evolution is determined by the properties of hot air for strong atmospheric explosion.

The phenomenon of the resonant activation (RA) of a particle over a fluctuating potential barrier with a four-value noise is investigated. It is shown that the mean first passage time (MFPT) displays six minima as the function of the transition rates γ1, γ2, γ3, γ4, γ5 and γ6 of the four-value noise, respectively. In addition, the effect of other parameters of the system, such as the noise strength D of the additive Gaussian white noise and the parameter value a, b, c, and d of the four-value noise, on the RAs is also investigated.

A constant-potential system driven by multiplicative dichotomous noise and subject to an input oscillatory signal is investigated. Two phenomena of stochastic resonance are observed. One is the response as a function of the noise's parameters; the other is that as a function of the input signal frequency. A phenomenon of multi-resonance (there are three or four peaks) is found for the response as a function of a parameter of the noise. A phenomenon of reverse-resonance is found, for which the response of the system to the signal can be weakened by the presence of the noise (there is an optimal minimum). These results help in studies of the systems with multiplicative dichotomous noise, such as the semiconductor, the proteins motor, the chemical reaction, and so on.

An electric circuit with dichotomous resistor is investigated. It is shown that the amplitude of the average electric current washing the resistor represents the phenomenon of stochastic resonance, which is the response as a function of the correlation time of the dichotomous resistor.

The effects of a quenched chaotic signal on the over-damped motion of the electron pairs of a superconducting junctions device are studied. It is shown that the chaotic signal can induce the net voltage and the phenomenon of resonance.

Transport of electron pairs in a superconducting junction device in the underdamped case is investigated. It is shown that the capacitance of the junctions can slow the movement of the electron pairs and reduce the net voltage. It is also shown that, for the underdamped case and the overdamped case, the movement of the electron pairs in this superconducting junctions device has some similar features. By controlling the correlation between the additive and multiplicative noise, the flux can be reversed. In addition, if the additive noise strength (or the temperature T) is large enough, a reversal can also be induced.

Stochastic resonance (SR) phenomenon of the system that is subject to the asymmetric two-state noise is investigated from the broad sense. It is shown that the amplitudes of the output signal exhibit the non-monotonic dependence on the input signal frequency ω, and the parameters describing the asymmetric two-state noise, such as the transition rate λ, the order parameter k describing the asymmetric degree of the two-state noise, and the noise strength D.

The phenomenon of stochastic resonance (SR) in a bistable nonlinear system is studied when the system is driven by the asymmetric potential and additive Gaussian colored noise. Using the unified colored noise approximation method, the additive Gaussian colored noise can be simplified to additive Gaussian white noise. The signal-to-noise ratio (SNR) is calculated according to the generalized two-state theory (shown in [H.S. Wio and S. Bouzat, Brazilian J. Phys. 29 (1999) 136]). We find that the SNR increases with the proximity of a to zero. In addition, the correlation time τ between the additive Gaussian colored noise is also an ingredient to improve SR. The shorter the correlation time τ between the Gaussian additive colored noise is, the higher of the peak value of SNR.

In this paper, we study spatially periodic system with infinite globally coupled oscillators driven by temporal-spatial noise and subject to a constant force. The results show that the system exhibits the phenomena of the non-equilibrium phase transition, transport of particles, and the anomalous hysteresis cycle for the mean field and the probability current.

The transport of the overdamped Brownian particles in a spatially periodic potential subject to the threevalue Poissonian noise in the stationary state is considered. We show that for the spatially periodic potential, no matter whether it is asymmetric, or is symmetric, flux can be induced. But the mechanism is different. The former is the common action of broken reflection symmetry and transition among three-value Poissonian noise in a cyclic way; the latter is single behavior of transition among three-value Poissonian noise in a cyclic way.

In this paper, we consider three kinds of temporal-spatial dichotomous noises. Three systems driven by these noises are studied, respectively. The master equations for these systems are derived.

In this paper, we study the transport of the system with the additive temporal-spatial noise, by two models, i.e., a spatial asymmetry model and a spatial symmetry model. The study shows that the correlation of the additive noise with the space and the spatial asymmetry are ingredients for the transport.

The transport of a spatially periodic system with infinite globally coupled oscillators driven by temporal-spatial noises is investigated. The probability current shows that the correlation of the multiplicative noises with the space, the spatial asymmetry, and the coupling among the different oscillators are ingredients for the transport of particles. It is a new phenomenon that the correlation of the multiplicative noises with the space can induce the nonzero flux.

In this paper, we investigate a four-dimensionally coupled system driven by dichotomous noise. A new kind of stochastic resonance is found, for which the response of the system to the input signal can be hugely intensified. We call it ``giant-resonance''.

In this paper we study the mean first passage time (MFPT) over a fluctuation potential barrier driven by a coupled noise. It is shown that the MFPT over the fluctuation potential barrier displays resonant activations as the function of the flipping rate of the fluctuation potential barrier, and as the function of the dichotomous noise transition rate.